ハイビジョンにおける字幕(クローズドキャプション)提示条件の検討

抄録

The optimal display condition of closed captions on the HDTV monitor is described. The character sizes of the captions in usual HDTV programs are almost over 48×48 dots. This is adapted for the previous subjective assessment tests. We had another test on the character length of captions using two subjective assessment scales. The 24 or more characters' length is desirable for making program enjoyable and easily understandable. A subjective assessment test on time differences between captions and pictures was also conducted using a drama program. Values of the time difference to be allowable deeply depend on contents of pictures. On the most severe condition, the value was within 1 second. In another case, 3 seconds caption delay was allowable.